The present invention relates to an information recording/reproducing system having a magnetic disk apparatus for recording/reproducing information and a host system capable of removably connecting the magnetic disk apparatus for making access thereto. More particularly, the present invention is concerned with an information recording/reproducing system in which the host system which is allowed to make access to the magnetic disk apparatus can be limited to a specific one.
There has been proposed a system designed for such application in which a magnetic disk apparatus is removably connected to a host system for recording/reproducing data such as motion pictures and sound in cooperation with an audio server, a video recorder, a portable information terminal, a car navigation system or the like. Because of the removable arrangement, such a problem is conceivable from the standpoint of security that a third party may unjustifiably dismount the magnetic disk apparatus to read/write information with the aid of another host system. As a technique for limiting the combination of the magnetic disk apparatus and the host system, there can be mentioned a mutual authentication processing in which authentication data is used. By way of example, JP-A-2001-256004 discloses a technique according to which one of the storage unit and the host system is designed to generate authentication data for an access control on the basis of authentication data generated by the other one to thereby perform the access control for the host system by using the first-mentioned authentication data. The authentication data is generated on the basis of the inherent information intrinsic to the storage unit or the host system and the date/time information. As the inherent information, the maker's name, machine identifier and/or serial number is used.